Astrocytes and oligodendrocytes in the thalamus jointly maintain synaptic activity by supplying metabolites

Thalamic astrocytes and oligodendrocytes are coupled via gap junctions and form panglial networks. Here, we show that these networks have a key role in energy supply of neurons. Filling an astrocyte or an oligodendrocyte in acute slices with glucose or lactate is sufficient to rescue the decline of stimulation-induced field post-synaptic potential (fPSP) amplitudes during extracellular glucose deprivation (EGD). In mice lacking oligodendroglial coupling, loading an astrocyte with glucose does not rescue the EGD-mediated loss of fPSPs. Monocarboxylate and glucose transporters are required for rescuing synaptic activity during EGD. In mice deficient in astrocyte coupling, filling of an oligodendrocyte with glucose does not rescue fPSPs during EGD. Our results demonstrate that, in the thalamus, astrocytes and oligodendrocytes are jointly engaged in delivering energy substrates for sustaining neuronal activity and suggest that oligodendrocytes exert their effect mainly by assisting astrocytes in metabolite transfer to the postsynapse

Barreloid borders and neuronal activity shape panglial gap junction-coupled networks in the mouse thalamus

The ventral posterior nucleus of the thalamus plays an important role in somatosensory information processing. It contains elongated cellular domains called barreloids, which are the structural basis for the somatotopic organization of vibrissae representation. So far, the organization of glial networks in these barreloid structures and its modulation by neuronal activity has not been studied. We have developed a method to visualize thalamic barreloid fields in acute slices. Combining electrophysiology, immunohistochemistry, and electroporation in transgenic mice with cell type-specific fluorescence labeling, we provide the first structure-function analyses of barreloidal glial gap junction networks. We observed coupled networks, which comprised both astrocytes and oligodendrocytes. The spread of tracers or a fluorescent glucose derivative through these networks was dependent on neuronal activity and limited by the barreloid borders, which were formed by uncoupled or weakly coupled oligodendrocytes. Neuronal somata were distributed homogeneously across barreloid fields with their processes running in parallel to the barreloid borders. Many astrocytes and oligodendrocytes were not part of the panglial networks. Thus, oligodendrocytes are the cellular elements limiting the communicating panglial network to a single barreloid, which might be important to ensure proper metabolic support to active neurons located within a particular vibrissae signaling pathway

Entwicklung von Prozessparametereinstellungen für das Laserstrahlschmelzen von Regolith unter Vakuum

Der Mond spielt eine wichtige Rolle bei der weiteren Erforschung und Entdeckung des Weltraums. Um den Mond für Weltraummissionen und -expeditionen nutzen zu können, ist es jedoch erforderlich, dass die dort verfügbaren Rohstoffe zur Herstellung von Infrastrukturen, Werkzeugen und Ersatzteilen nutzbar werden. Aktuell steht auf dem Mond ausschließlich Regolith als zugängliches Grundmaterial zur Verfügung. Deshalb wird ein Fertigungsverfahren benötigt, mit dem dieses verarbeitet werden kann. Im Rahmen des Projektes „Erprobung des mobilen selektiven Laserschmelzens von Regolith auf der Mondoberfläche mit Hilfe von künstlicher Intelligenz“ (MOONRISE-FM) wird ein mobiles Laserstrahlschmelzverfahren entwickelt, bei dem durch das Aufschmelzen des Regoliths mit einer weltraumtauglichen Laserstrahlquelle ein- und zweidimensionale Objekte auf dem Mond hergestellt werden sollen. Um geeignete Prozessparametereinstellungen zunächst auf der Erde zu entwickeln, werden Regolithsimulate und ein Versuchsaufbau, der die Umgebungsbedingungen auf dem Mond bestmöglich abbildet, benötigt. In diesem Artikel wird die Entwicklung von geeigneten Prozessparametereinstellungen für die Laserleistung und die Belichtungsstrategie beim eindimensionalen Laserstrahlschmelzen eines Regolithsimulates unter Vakuum mit Hilfe von statistischer Versuchsplanung vorgestellt. Außerdem werden die mit dem Versuchsaufbau hergestellten Proben bezüglich ihrer Masse, räumlichen Ausprägung und Porosität untersucht. Darauf aufbauend wird bestimmt, welche potentiellen Abweichungen zwischen dem Versuchsaufbau und der realen Mondumgebung bestehen und welchen Einfluss diese auf den Laserstrahlschmelzprozess haben

Characterization of panglial gap junction networks in the thalamus, neocortex, and hippocampus reveals a unique population of glial cells

The thalamus plays important roles as a relay station for sensory information in the central nervous system (CNS). Although thalamic glial cells participate in this activity, little is known about their properties. In this study, we characterized the formation of coupled networks between astrocytes and oligodendrocytes in the murine ventrobasal thalamus and compared these properties with those in the hippocampus and cortex. Biocytin filling of individual astrocytes or oligodendrocytes revealed large panglial networks in all 3 gray matter regions. Combined analyses of mice with cell type-specific deletion of connexins (Cxs), semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blotting showed that Cx30 is the dominant astrocytic Cx in the thalamus. Many thalamic astrocytes even lack expression of Cx43, while in the hippocampus astrocytic coupling is dominated by Cx43. Deletion of Cx30 and Cx47 led to complete loss of panglial coupling, which was restored when one allele of either Cxs was present. Immunohistochemistry revealed a unique antigen profile of thalamic glia and identified an intermediate cell type expressing both Olig2 and Cx43. Our findings further the emerging concept of glial heterogeneity across brain regions